Sec 19 Q17 DS1000

[gviren]

The OA is E, I think it should be C


1) aba=a so a^2b-a=0
a(ab-1) = 0

so either a=0 or ab=1

2)

aba=b so b^2a-b=0
b(ab-1) = 0

so either b=0 or ab=1

combining 1 and 2, ab=1


Please help

[jayhawk2001]

Combining (1) and (2), we still have 2 options -- ab = 1, or (a=0, b=0)

Please note that (1) and (2) are both satisfied for a = 0, b = 0

Hence E